The invention relates to a method for exhaust gas aftertreatment in which an exhaust gas to be aftertreated, which is produced during a combustion of a fuel, is treated with a reducing agent.
The invention further relates to a combustion system having a combustion chamber in which a fuel is combustible, a store from which the combustion chamber can be supplied with a constituent of the fuel, and a reducing chamber.
The invention also relates to a use of a constituent of a fuel.
It is known to use methods for exhaust gas aftertreatment in industrial installations, in particular in power plants and/or in motor vehicles, in particular in motor vehicles with an internal combustion engine. An aftertreatment of an exhaust gas formed on operation of an industrial installation or a power plant may be necessary, for example, when legally prescribed emission and exhaust gas standards have to be observed.
Emission and exhaust gas standards have the purpose of protecting humans and the environment. Some of the substances contained in exhaust gases, in particular nitrogen oxides (NOx) can have harmful effects on humans and the environment. These substances can lead to an irritation or damage to respiratory organs or to the formation of acid rain, smog and/or to the acceleration of global warming.
In order to reduce a number of such harmful substances in the exhaust gas, it is known to treat/aftertreat the exhaust gas with a reducing agent, for example ammonia (NH3). An example of a method in which the exhaust gas is aftertreated with a reducing agent is “selective catalytic reduction”, SCR. In particular in an exhaust gas denitrification, selective catalytic reduction has become established due to its efficiency as compared with other methods.
However, the aftertreatment of the exhaust gas with a reducing agent has so far also entailed some disadvantages. For example, a store for the reducing agent is necessary. Additional space is thus required which, in particular in motor vehicles, is of critical importance due to their limited space provision. Under certain circumstances, a plurality of stores may be necessary for the reducing agent or for individual constituents of the reducing agent. This can be the case, in particular, if individual constituents of the reducing agent can or may not be stored in a common store due to their chemical properties.
Furthermore, a state, in particular a fill level of the reducing agent or its constituents must be monitored and, if necessary, the reducing agent or one of its constituents must be replenished or exchanged. This is associated with a certain maintenance effort.
Depending on what type of substance/substance mixture is used as the reducing agent, the reducing agent can be corrosive/corrosion promoting so that materials which come into contact with the reducing agent should be corrosion free. Such materials can, under certain circumstances, be complex and/or expensive to manufacture.
Furthermore, energy is required for manufacturing the reducing agent, and this is associated with certain costs. Depending on which manufacturing method is used, during the production of the reducing agent, CO2 emissions can occur which contribute to the reinforcing of global warming.
From DE 10 2007 021 827 A1, DE 10 2006 000 401 A1, EP 0 537 968 A1, DE 10 2011 011 952 A1 and DE 10 2011 115 300 A1, various combustion systems with a respective exhaust gas aftertreatment thereat for an exhaust gas of the combustion system are known, wherein the combustion system and the exhaust gas aftertreatment are operated with a constituent of the fuel of the combustion system.